Multiple-ratio automatic transmission control method and system for ratio upshifts

• US 8,529,406 B2
• Filed: 11/30/2012
• Issued: 09/10/2013
• Est. Priority Date: 01/25/2010
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Fujii, Yujii, Asgari, Jahan, Hrovat, Davorin David, Jiang, Hong, Pietron, Gregory Michael, Riedle, Bradley Dean, Teslak, Christopher John, Tseng, Hongtei Eric
• Primary Examiner(s): Wright, Dirk
• Application Number:
  US13/690,501
• Publication Number:
  US 20130090818A1
• Time in Patent Office: 284 Days
• Field of Search: 477/155
• US Class Current: 477/155
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/08 including control of electric propulsion units, e.g. motors or generators
• CPC Class Codes: B60W 10/11 Stepped gearings
• CPC Class Codes: B60W 10/115 with planetary gears
• CPC Class Codes: B60W 30/19 Improvement of gear change, e.g. by synchronisation or smoothing gear shift
• CPC Class Codes: F16H 2342/044 Torque transmitting capability
• CPC Class Codes: F16H 61/061 using electric control means
• CPC Class Codes: F16H 61/686 with orbital gears

Abstract

A speed ratio shaft control for multiple ratio vehicle transmission has controlled release of an off-going transmission clutch and controlled engagement of an on-coming transmission clutch during a speed ratio upshift, at least one clutch being a friction torque establishing clutch. A controller, using shift-timing software strategy, actively manages in real time a clutch torque level for each clutch so that transient torque disturbances in a transmission torque output shaft are mitigated.

Claims

1. A multiple-ratio transmission wherein a powertrain source provides an input torque to the transmission, the transmission comprising:

oncoming and off-going clutches for effecting ratio shifts;

a controller, during a ratio upshift event, configured to;

increase torque capacity of the oncoming clutch while torque capacity of the off-going is reduced and maintained locked;

increase the input torque during a torque phase before start of an inertia phase; and

decrease transmission input torque at a controlled rate during the inertia phase;

thereby minimizing torque transients along the output shaft during the upshift.

2. The multiple-ratio transmission set forth in claim 1, wherein the off-going coupling is an overrunning coupling adapted to brake a reaction gear element of the transmission whereby the upshift is a non-synchronous upshift.

3. The multiple-ratio transmission as set forth in claim 1, wherein the torque phase of an upshift is preceded by a preparatory phase, and the controller is configured to:

decrease torque capacity of the off-going clutch during the preparatory phase to a value that is sufficient to keep the off-going clutch locked at the start of the torque phase, such that the torque capacity of the off-going clutch during the torque phase maintains the off-going clutch locked without slipping until the end of the torque phase.

4. The multiple-ratio transmission as set forth in claim 1, wherein the controller is further configured to:

choose a desired output shaft torque at the start of a torque phase of the upshift;

determine a desired off-going clutch torque based on a desired output shaft torque;

calculate an on-coming clutch torque capacity as a function of desired output shaft torque, gear ratio for a high gear ratio configuration, and gear ratio for a lower gear ratio configuration;

calculate a transmission input shaft torque as a function of torque capacity of one of the oncoming or off-going clutches; and

release the one of the oncoming or off-going clutches at the end of the torque phase if the torque capacity of the other oncoming or off-going clutches is less than a pre-calibrated threshold as an inertia phase begins.

5. The multiple-ratio transmission as set forth in claim 1, wherein the torque capacity of the one oncoming or off-going clutches is determined in the inertia phase as a function of desired output shaft torque and an upshift gear ratio.

6. The multiple-ratio transmission set forth in claim 4, wherein calculating the transmission input shaft torque is repeated in a closed loop control if the torque capacity of the other of the oncoming or off-going clutches is greater than a pre-calibrated threshold.

7. A method for controlling an upshift of a multiple-ratio vehicle transmission comprising:

increasing torque capacity of an oncoming clutch while torque capacity of an off-going clutch is reduced and maintains locked;

increasing a transmission input torque during a torque phase before start of an inertia phase; and

decreasing the input torque during the inertia phase,

thereby minimizing torque transients during the upshift.

8. The method set forth in claim 7, further comprising decreasing torque capacity of the oncoming clutch at the start of the inertia phase.

9. The method set forth in claim 7, wherein the off-going clutch comprises an overrunning coupling adapted to brake a reaction gear element of the transmission, whereby the upshift is a non-synchronous upshift.

10. The method set forth in claim 7, wherein the torque phase of an upshift is preceded by a preparatory phase, and the method further comprising:

decreasing torque capacity of the off-going clutch during the preparatory phase to a value that is sufficient to keep the off-going clutch locked at the start of the torque phase, such that the torque capacity of the off-going clutch during the torque phase maintains the off-going clutch locked without slipping until the end of the torque phase.

11. The method set forth in claim 7, further comprising:

choosing a desired output shaft torque at the start of a torque phase of the upshift;

determining a desired off-going clutch torque based on a desired output shaft torque;

calculating an on-coming clutch torque capacity as a function of desired output shaft torque, gear ratio for a high gear ratio configuration, and gear ratio for a lower gear ratio configuration;

calculating a transmission input shaft torque as a function of torque capacity of one of the oncoming or off-going clutches; and

releasing the one of the oncoming or off-going clutches at the end of the torque phase if the torque capacity of the other oncoming or off-going clutches is less than a pre-calibrated threshold as an inertia phase begins.

12. The method set forth in claim 11, wherein the torque capacity of the one oncoming or off-going clutches is determined in the inertia phase as a function of desired output shaft torque and an upshift gear ratio.

13. The method set forth in claim 11, wherein calculating the transmission input shaft torque is repeated in a closed loop control if the torque capacity of the other of the oncoming or off-going clutches is greater than a pre-calibrated threshold.

14. A control system for a multiple-ratio transmission comprising:

a controller for activating oncoming and off-going clutches during ratio shifts, wherein, during a ratio upshift, the controller is configured to;

increase an oncoming clutch torque capacity while an off-going clutch torque capacity is reduced and maintained locked;

increase a transmission input torque during a torque phase before start of an inertia phase;

decreasing the input torque during the inertia phase; and

decreasing the oncoming clutch torque capacity during the inertia phase.

15. The control system set forth in claim 14, wherein the off-going clutch comprises an overrunning coupling adapted to brake a reaction gear element of the transmission, whereby the upshift is a non-synchronous upshift.

16. The control system set forth in claim 14, wherein the torque phase of an upshift is preceded by a preparatory phase, and the controller is further configured to:

decrease torque capacity of the off-going clutch during the preparatory phase to a value that is sufficient to keep the off-going clutch locked at the start of the torque phase, such that the torque capacity of the off-going clutch during the torque phase maintains the off-going clutch locked without slipping until the end of the torque phase.

17. The control system set forth in claim 14, wherein the controller is further configured to:

choose a desired output shaft torque at the start of a torque phase of the upshift;

determine a desired off-going clutch torque based on a desired output shaft torque;

calculate an on-coming clutch torque capacity as a function of desired output shaft torque, gear ratio for a high gear ratio configuration, and gear ratio for a lower gear ratio configuration;

calculate a transmission input shaft torque as a function of torque capacity of one of the oncoming or off-going clutches; and

release the one of the oncoming or off-going clutches at the end of the torque phase if the torque capacity of the other oncoming or off-going clutches is less than a pre-calibrated threshold as an inertia phase begins.

18. The control system set forth in claim 17, wherein the torque capacity of the one oncoming or off-going clutches is determined in the inertia phase as a function of desired output shaft torque and an upshift gear ratio.

19. The control system set forth in claim 17, wherein calculating the transmission input shaft torque is repeated in a closed loop control if the torque capacity of the other of the oncoming or off-going clutches is greater than a pre-calibrated threshold.